There are three different kinds of blood in cats: A, AB, and B. Blood type A is the most common, while blood type B is common or rare depending on the breed and blood type AB is rare in all cats. Most of us don't really think about our cats blood types, but it's actually more important than you might think - a life and death kind of importance for breeding cats. I had a personal experience with this from one of our cats: Hannah.
Antibodies and Neonatal Isoerythrolysis
Cats naturally have antibodies in their blood against the opposite blood type. This is to prevent infection and to reject foreign proteins. Type B cats have especially strong antibodies against type A. Type AB is the only blood type without any antibodies.
This is a good thing. Antibodies are passed from mother to kitten through the colostrum of the nursing female to give the kittens protection against diseases. But this is a very bad thing when you're dealing with different blooded cats. Should the kittens inherit the opposite blood type of the blood type A mother, the kittens could suffer from a disease called Neonatal Isoerythrolysis, also known as Fading Kitten Syndrome. If a type B mother cat's blood type differs from her kittens, the antibodies in the Queen's colostrum destroy the type A kittens red blood cells, causing Anemia.
I didn't know about any of this at the time. I had looked at Hannah's DNA test but I never thought anything of her type B blood, so I bred Hannah to one of our toms. All her previous pregnancies had turned out fine. And everything seemed okay at first with this one too; the pregnancy was fine, the birth was fine, even the first few days were fine. Hannah had four healthy kittens. But over the next few days I started noticing something off about two of Hannah's kittens, which only worsened as the days went on.
Signs of Neonatal Isoerythrolysis
There are many signs of the Fading Kitten Syndrome. This disease can affect kittens in a variety of ways. Mostly due to the amount of colostrum the kitten drinks. The signs of Neonatal Isoerythrolysis are:
- Sudden death, with no prior warning or symptoms.
- Most kittens affected with this will fade over a few days. They stop sucking from the queen, become weak, and can appear pale or yellow colored (jaundiced).
- Kittens effected usually pass red colored urine, because of the presence of hemoglobin (released from the breakdown of red blood cells) in the urine.
- Kittens mildly affected with this may show little signs, but the tip of their tails and ears start to die off due to the lack of blood in the kittens extremities.
- Some kittens may remain unaffected and show no signs of disease.
The first kitten that died did so relatively quickly within the first couple days without warning. I had also started to notice one of the other kittens becoming skinnier and skinnier as the days grew on.
He was constantly being pushed out of the way by the other kittens any time he tried to nurse. Hannah was also starting to reject him. I would often find him pushed out of the whelping box. I tried for several days to get him to nurse, but every time he would get pushed out of the way by the others or simply unable to latch on. Eventually I bought some kitten formula and tried to nurse him by bottle, but he was barely strong enough to even swallow. He passed that same day.
Two out of the four kittens survived. Jackson and Tina. Meaning the remaining two are most definitely blood type B's like Hannah.
Prevention of Neonatal Isoerythrolysis
Treatment for Neonatal Isoerythrolysis is rarely possible. The best way to treat it is to prevent it in the first place.
- Avoid breeding type B's altogether. Which may limit your breeding pool.
- Only breeding type B queens with blood type B toms. This would solve the problem and can increase the population of blood type B's in that certain breed. It could, again, limit your breeding pool.
- Separate the blood type A's from the type B queen during the first 24 hours of life. This method has been used by many breeders, and has been very successful. This requires blood typing the kittens using the blood from the umbilical cord and separating those that are blood type A or AB from the mother. The blood type B's can be left to suckle from the queen. The removed kittens need to be fed by bottle or put with a type A queen that is producing milk. Afterwards it's safe to return the type A or AB kittens to the mother as the blood type B queen should not be producing anymore colostrum.
To conclude, I hope this helped those who didn't know about this. We've learned this the hard way, but I hope it isn't that way for you if you plan to breed. We are retiring Hannah this year due to her blood type among a few other reasons. So she's currently looking for her new home. One of Hannah's kittens, Tina, is also looking for a guardian of her own. If you're interested, let me know! They would both make an amazing companion.
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